Glucocorticoids support the activation of IgE ⁺ B cells and promote IgE production without global changes in chromatin accessibility. (A) Multidimensional scaling plot representing relative positions for Cont vs. DEX-treated total B cells (Cont and DEX) or IgE⁺ B cells sorted postculture (ContIgE⁺ and DEXIgE⁺). x and y axes represent leading log₂(CPM fold change) for DEX/Cont in the first and second dimension, respectively (n = 2 mice/group as biological replicates). (B) Percentage of IgE⁺ IgG1⁻ B cells (within live B220⁺) from B cells cultured with Cont vehicle (gray) or DEX (red) without or with TPCA-1 (n = 3 mice/group). (C) Chromatin accessibility within the IgH locus of Cd19-Cre^+/− GR Het vs. cKO B cells upon DEX treatment, determined by ATAC-seq. 100 kb scale is shown for IgH, with blue boxes representing exons (top). Dashed lines designate a magnified view of Ighe (bottom; n = 1–3 pooled mice/sample with n = 2 samples/group). (D) Percentages of IgE⁺ or IgG1⁻ B cells at each cell division within B220⁺ cells after 96 h, determined by CellTrace labeling (n = 3 mice/group). (E) Ratio of percentage of IgE⁺ to IgG1⁺ B cells within live B220⁺ CD93⁻ cells (gray) or within live B220⁺ CD93⁺ cells (red) from WT Cont B cells (left), and absolute percentage of IgG1⁺ IgE⁻ B cells (within live B220⁺ CD93⁺) from Cont (gray) or DEX-treated (red) Cd19-Cre^+/− GR Het vs. cKO B cells (right; n = 19 mice/group, compiled from six independent experiments [left]; n = 5 mice/group, compiled from two independent experiments [right]). Error bars in B, D, and E represent SEM. P values <0.05 were considered significant (*, P < 0.05; **, P < 0.01; ****, P < 0.0001; unlabeled, not significant). Ratio paired Student’s t test was used for B and E, and two-way ANOVA with post hoc Šídák’s multiple comparisons test was used for D.